Question

You are going to mix a gallon bucket of window cleaner. The instructions direct you to mix 1 part cleaner to 3 parts water. How much cleaning solution will you need to use?*

Answer 1

25% I believe because it is at least 1 part cleaner and 3 parts water so you would have to add all the parts which means it would be 1/4 plus 3/4 and since you only have one part cleaner thats where you would get 25%

Answer 2

To mix cleaner and water you need to divide the bucket's capacity into 4.It's easy in this case as gallon is divided into quarts (1 gallon = 4 quarts).We know that one part will be cleaner, it means that you will need to use 1 quart of the cleaner.  
hope thats right